John Smeaton by George Romney, 1779 (detail), National Portrait Gallery, London

John SmeatonFRS (8 June 1724 – 28 October 1792) was an English civil engineer responsible for the design of bridges, canals, harbours and lighthouses. He was also a capable mechanical engineer and an eminent physicist. Smeaton was the first self-proclaimed civil engineer, and often regarded as the "father of civil engineering".

He was elected a Fellow of the Royal Society in 1753, and in 1759 won the Copley Medal for his research into the mechanics of waterwheels and windmills. His 1759 paper "An Experimental Enquiry Concerning the Natural Powers of Water and Wind to Turn Mills and Other Machines Depending on Circular Motion"[2] addressed the relationship between pressure and velocity for objects moving in air (Smeaton noted that the table doing so was actually contributed by "my friend Mr Rouse" "an ingenious gentleman of Harborough, Leicestershire" and calculated on the basis of Rouse's experiments), and his concepts were subsequently developed to devise the 'Smeaton Coefficient'.[3] Smeaton's water wheel experiments were conducted on a small scale model with which he tested various configurations over a period of seven years.[4] The resulting increasing efficiency in water power contributed to the Industrial Revolution.

Recommended by the Royal Society, Smeaton designed the third Eddystone Lighthouse (1755–59). He pioneered the use of 'hydraulic lime' (a form of mortar that will set under water) and developed a technique involving dovetailed blocks of granite in the building of the lighthouse. His lighthouse remained in use until 1877 when the rock underlying the structure's foundations had begun to erode; it was dismantled and partially rebuilt at Plymouth Hoe where it is known as Smeaton's Tower. He is important in the history, rediscovery of, and development of modern cement, because he identified the compositional requirements needed to obtain "hydraulicity" in lime; work which led ultimately to the invention of Portland cement. Portland cement led to the re-emergence of concrete as a modern building material, largely due to Smeaton's influence.

Because of his expertise in engineering, Smeaton was called to testify in court for a case related to the silting-up of the harbour at Wells-next-the-Sea in Norfolk in 1782: he is considered to be the first expert witness to appear in an English court. He also acted as a consultant on the disastrous 63-year-long New Harbour at Rye, designed to combat the silting of the port of Winchelsea. The project is now known informally as "Smeaton's Harbour", but despite the name his involvement was limited and occurred more than 30 years after work on the harbour commenced.[8]

In 1789 Smeaton applied an idea by Denis Papin, by using a force pump to maintain the pressure and fresh air inside a diving bell.[9][10] This bell, built for the Hexham bridge project, was not intended for underwater work, but in 1790 the design was updated to enable it to be used underwater on the breakwater at Ramsgate Harbour.[10] Smeaton is also credited with explaining the fundamental differences and benefits of overshot versus undershot water wheels.

Smeaton experimented with the Newcomen steam engine and made marked improvements around the time James Watt was building his first engines (ca. late 1770s).[11]

John Smeaton Academy, a secondary school in the suburbs of Leeds adjacent to the Pendas Fields estate near Austhorpe, is named after Smeaton. He is also commemorated at the University of Plymouth, where the Mathematics and Technology Department is housed in a building named after him. A viaduct in the final stage of the Leeds Inner Ring Road, opened in 2008, was named after him.

He is mentioned in the song "I Predict a Riot" (as a symbol of a more dignified and peaceful epoch in Leeds history; and in reference to a Junior School House at Leeds Grammar School, which lead singer Ricky Wilson attended) by the indie rock band Kaiser Chiefs, who are natives of Leeds.

k{\displaystyle k} is the Smeaton coefficient- 0.005 (the drag in pounds weight of a 1-square-foot (0.093 m2) plate at 1 mph) was the value as determined by Smeaton,[16] later corrected to 0.0033 by the Wright brothers

Cl{\displaystyle C_{l}} is the lift coefficient (the lift relative to the drag of a plate of the same area)